Modeling and analysis of leading edge ribs of an aircraft wing

Abstract

An apparatus is provided for analysis of a leading edge rib of a fixed leading edge section of an aircraft wing. The apparatus may identify geometric or inertial properties of a plurality of stiffeners of the rib, and based thereon perform an analysis to predict a failure rate of the leading edge rib under an external load. From the failure rate, the apparatus may determine a structural integrity of the leading edge rib under the external load. Performing the analysis may include importing a plurality of section cuts into a finite element model of the rib and thereby identifying nodes proximate the section cuts. Under an external load, internal load distributions may be extracted from elements proximate the nodes and elements, and the failure rate of the leading edge rib under the external load may be predicted based on the internal load distributions of the elements.

What is claimed is: 
     
       1. An apparatus for design of a leading edge rib of a fixed leading edge section of an aircraft wing, the leading edge rib including a plurality of stiffeners, the apparatus comprising a processor and a memory storing executable instructions that, in response to execution by the processor, cause the apparatus to at least:
 generate a three-dimensional (3D) model of the fixed leading edge section of the aircraft wing; 
 identify one or more geometric or inertial properties of the plurality of stiffeners; and 
 perform a computer-aided engineering, structural analysis to predict a failure rate of the leading edge rib under an external load using the one or more geometric or inertial properties of the plurality of stiffeners, and from the failure rate, determine a structural integrity of the leading edge rib under the external load, including the apparatus being caused to:
 import a plurality of section cuts into a finite element model of the leading edge rib, each section cut forming a cross-section corresponding to and having the one or more geometric or inertial properties of a respective stiffener of the plurality of stiffeners; 
 identify respective nodes and elements of the finite element model proximate the plurality of section cuts so imported; 
 apply the external load to the finite element model, and thereunder extract internal load distributions of elements of the finite element model proximate the respective nodes and elements; and 
 predict the failure rate of the leading edge rib under the external load based on the internal load distributions of the elements, 
 
 the structural integrity including a margin of safety of the leading edge rib; and when the margin of safety is negative, 
 iteratively adjust the one or more geometric or inertial properties of the plurality of stiffeners based on the margin of safety, and repeat the computer-aided engineering, structural analysis, until the margin of safety is positive; and 
 update the 3D model with the one or more geometric or inertial properties of the plurality of stiffeners as adjusted such that the plurality of stiffeners and thereby the leading edge rib are resized within the 3D model. 
 
     
     
       2. The apparatus of  claim 1 , wherein the apparatus being caused to identify the respective nodes and elements of the finite element model proximate the plurality of section cuts so imported, includes being caused to therefrom respectively identify an outermost node for each of the plurality of section cuts so imported, and the memory stores further executable instructions that, in response to execution by the processor, cause the apparatus to further at least:
 define Cartesian coordinate systems that originate at the outermost nodes and that have a common orientation, and 
 wherein the apparatus being caused to extract internal load distributions includes, for each axis of each of the Cartesian coordinate systems that originate at the outermost nodes, the apparatus being caused to extract the internal load distributions of the elements on a negative half of the axis proximate the outermost node. 
 
     
     
       3. The apparatus of  claim 2 , wherein the apparatus being caused to identify the outermost node includes the outermost node being a common node of elements of the finite element model that represent the flange and web, the common node representing a point of intersection therebetween. 
     
     
       4. The apparatus of  claim 2 , wherein the apparatus being caused to extract the internal load distributions of the elements on the negative half of the axis includes being caused to extract six (6) load components, and the apparatus being caused to predict the failure rate includes being caused to predict the failure rate under the external load based on the six load components. 
     
     
       5. The apparatus of  claim 1 , wherein the one or more geometric or inertial properties of the cross-section include at least a cross-section type, dimensional measurements, centroid or moment of inertia of the cross-section. 
     
     
       6. The apparatus of  claim 5 , wherein the apparatus being caused to identify the one or more geometric or inertial properties includes being caused to:
 output the one or more geometric or inertial properties including the dimensional measurements, centroid or moment of inertia of the cross-section into a spreadsheet file; and 
 export the cross-section type into an Initial Graphics Exchange Specification (IGES) file, and the apparatus being caused to import the plurality of section cuts includes being caused to import the plurality of section cuts using the spreadsheet file and IGES file. 
 
     
     
       7. The apparatus of  claim 1 , wherein the apparatus being caused to identify the one or more geometric or inertial properties of the plurality of stiffeners includes being caused to:
 produce a model including a one-dimensional (1D) curve model, two-dimensional (2D) surface model or a combination thereof from a 3D model of the fixed leading edge section of the aircraft wing; and therefrom, 
 identify the one or more geometric or inertial properties of the plurality of stiffeners based at least in part on the model including the 1D curve model, 2D surface model or the combination thereof. 
 
     
     
       8. The apparatus of  claim 7 , wherein the apparatus being caused to import the plurality of section cuts into the finite element model of the leading edge rib includes being caused to:
 import the plurality of section cuts into the finite element model as exported from the 1D curve model, 2D surface model or the combination thereof, the one or more geometric or inertial properties thereby being based on the model including the 1D curve model, 2D surface model or the combination thereof. 
 
     
     
       9. The apparatus of  claim 1 , wherein the respective stiffener includes at least a flange and web, and the elements of the finite element model include bar and shell elements respectively representing flanges and webs of the plurality of stiffeners. 
     
     
       10. A method for design of a leading edge rib of a fixed leading edge section of an aircraft wing, the leading edge rib including a plurality of stiffeners, the method comprising:
 generating a three-dimensional (3D) model of the fixed leading edge section of the aircraft wing; 
 identifying one or more geometric or inertial properties of the plurality of stiffeners; and 
 performing a computer-aided engineering, structural analysis to predict a failure rate of the leading edge rib under an external load using the one or more geometric or inertial properties of the plurality of stiffeners, and from the failure rate, determining a structural integrity of the leading edge rib under the external load, including:
 importing a plurality of section cuts into a finite element model of the leading edge rib, each section cut forming a cross-section corresponding to and having the one or more geometric or inertial properties of a respective stiffener of the plurality of stiffeners; 
 identifying respective nodes and elements of the finite element model proximate the plurality of section cuts so imported; 
 applying the external load to the finite element model, and thereunder extracting internal load distributions of elements of the finite element model proximate the respective nodes and elements; and 
 predicting the failure rate of the leading edge rib under the external load based on the internal load distributions of the elements, 
 
 the structural integrity including a margin of safety of the leading edge rib; and when the margin of safety is negative, 
 iteratively adjusting the one or more geometric or inertial properties of the plurality of stiffeners based on the margin of safety, and repeating the computer-aided engineering structural analysis, until the margin of safety is positive; and 
 updating the 3D model with the one or more geometric or inertial properties of the plurality of stiffeners as adjusted such that the plurality of stiffeners and thereby the leading edge rib are resized within the 3D model. 
 
     
     
       11. The method of  claim 10  wherein identifying the respective nodes and elements of the finite element model proximate the plurality of section cuts so imported, includes therefrom respectively identifying an outermost node for each of the plurality of section cuts so imported, and the method further comprises:
 defining Cartesian coordinate systems that originate at the outermost nodes and that have a common orientation, and 
 extracting internal load distributions includes, for each axis of each of the Cartesian coordinate systems that originate at the outermost nodes, extracting the internal load distributions of the elements on a negative half of the axis proximate the outermost node. 
 
     
     
       12. The apparatus of  claim 11 , wherein identifying outermost nodes of the finite element model includes the outermost nodes being an outermost common node of elements of the finite element model that represent the flange and web, the outermost common node representing a point of intersection therebetween. 
     
     
       13. The method of  claim 11 , wherein extracting the internal load distributions of the elements on the negative half of the axis includes being caused to extract six (6) load components, and predicting the failure rate includes being caused to predict the failure rate under the external load based on the six load components. 
     
     
       14. The method of  claim 10 , wherein the one or more geometric or inertial properties of the cross-section include at least a cross-section type, dimensional measurements, centroid or moment of inertia of the cross-section. 
     
     
       15. The method of  claim 14 , wherein identifying the one or more geometric or inertial properties includes:
 outputting the one or more geometric or inertial properties including the dimensional measurements, centroid or moment of inertia of the cross-section into a spreadsheet file; and 
 exporting the cross-section type into an Initial Graphics Exchange Specification (IGES) file, and importing the plurality of section cuts includes being caused to import the plurality of section cuts using the spreadsheet file and IGES file. 
 
     
     
       16. The method of  claim 10 , wherein identifying the one or more geometric or inertial properties of the plurality of stiffeners includes:
 producing a model including a one-dimensional (1D) curve model, two-dimensional (2D) surface model or a combination thereof from a 3D model of the fixed leading edge section of the aircraft wing; and therefrom, 
 identifying the one or more geometric or inertial properties of the plurality of stiffeners based at least in part on the model including the 1D curve model, 2D surface model or the combination thereof. 
 
     
     
       17. The method of  claim 16 , wherein importing the plurality of section cuts into the finite element model of the leading edge rib includes:
 importing the plurality of section cuts into the finite element model as exported from the 1D curve model, 2D surface model or the combination thereof, the one or more geometric or inertial properties thereby being based on the model including the 1D curve model, 2D surface model or the combination thereof. 
 
     
     
       18. The apparatus of  claim 10 , wherein the respective stiffener includes at least a flange and web, and the elements of the finite element model include bar and shell elements respectively representing flanges and webs of the plurality of stiffeners. 
     
     
       19. A computer-readable storage medium for design of a leading edge rib of a fixed leading edge section of an aircraft wing, the leading edge rib including a plurality of stiffeners, the computer-readable storage medium being non-transitory and having computer-readable program code portions stored therein that in response to execution by a processor, cause an apparatus to at least:
 identify one or more geometric or inertial properties of the plurality of stiffeners; and 
 perform a computer-aided engineering, structural analysis to predict a failure rate of the leading edge rib under an external load using the one or more geometric or inertial properties of the plurality of stiffeners, and from the failure rate, determine a structural integrity of the leading edge rib under the external load, including the apparatus being caused to:
 import a plurality of section cuts into a finite element model of the leading edge rib, each section cut forming a cross-section corresponding to and having the one or more geometric or inertial properties of a respective stiffener of the plurality of stiffeners; 
 identify respective proximate nodes and elements of the finite element model proximate the plurality of section cuts so imported; 
 apply the external load to the finite element model, and thereunder extract internal load distributions of elements of the finite element model proximate the respective nodes and elements; and 
 predict the failure rate of the leading edge rib under the external load based on the internal load distributions of the elements, 
 
 the structural integrity including a margin of safety of the leading edge rib; and when the margin of safety is negative, 
 iteratively adjust the one or more geometric or inertial properties of the plurality of stiffeners based on the margin of safety, and repeat the computer-aided engineering, structural analysis, until the margin of safety is positive; and 
 update the 3D model with the one or more geometric or inertial properties of the plurality of stiffeners as adjusted such that the plurality of stiffeners and thereby the leading edge rib are resized within the 3D model. 
 
     
     
       20. The computer-readable storage medium of  claim 19 , wherein the memory stores further executable instructions that, in response to execution by the processor, cause the apparatus to further at least define Cartesian coordinate systems that originate at the respective node s and that have a common orientation, and
 wherein the apparatus being caused to extract internal load distributions includes, for each axis of each of the Cartesian coordinate systems that originates at a node of the respective nodes, the apparatus being caused to extract the internal load distributions of the elements on a negative half of the axis proximate the node. 
 
     
     
       21. The computer-readable storage medium of  claim 20 , wherein the apparatus being caused to identify the outermost node includes the outermost node being an outermost common node of elements of the finite element model that represent the flange and web, the outermost common node representing a point of intersection therebetween. 
     
     
       22. The computer-readable storage medium of  claim 20 , wherein the apparatus being caused to extract the internal load distributions of the elements on the negative half of the axis includes being caused to extract six (6) load components, and the apparatus being caused to predict the failure rate includes being caused to predict the failure rate under the external load based on the six load components. 
     
     
       23. The computer-readable storage medium of  claim 19 , wherein the one or more geometric or inertial properties of the cross-section include at least a cross-section type, dimensional measurements, centroid or moment of inertia of the cross-section. 
     
     
       24. The computer-readable storage medium of  claim 23 , wherein the apparatus being caused to identify the one or more geometric or inertial properties includes being caused to:
 output the one or more geometric or inertial properties including the dimensional measurements, centroid or moment of inertia of the cross-section into a spreadsheet file; and 
 export the cross-section type into an Initial Graphics Exchange Specification (IGES) file, and the apparatus being caused to import the plurality of section cuts includes being caused to import the plurality of section cuts using the spreadsheet file and IGES file. 
 
     
     
       25. The apparatus of  claim 19 , wherein the apparatus being caused to identify the one or more geometric or inertial properties of the plurality of stiffeners includes being caused to:
 produce a model including a one-dimensional (1D) curve model, two-dimensional (2D) surface model or a combination thereof from a 3D model of the fixed leading edge section of the aircraft wing; and therefrom, 
 identify the one or more geometric or inertial properties of the plurality of stiffeners based at least in part on the model including the 1D curve model, 2D surface model or the combination thereof. 
 
     
     
       26. The apparatus of  claim 25 , wherein the apparatus being caused to import the plurality of section cuts into the finite element model of the leading edge rib includes being caused to:
 import the plurality of section cuts into the finite element model as exported from the 1D curve model, 2D surface model or the combination thereof, the one or more geometric or inertial properties thereby being based on the model including the 1D curve model, 2D surface model or the combination thereof. 
 
     
     
       27. The computer-readable storage medium of  claim 26 , wherein the respective stiffener includes at least a flange and web, and the elements of the finite element model include bar and shell elements respectively representing flanges and webs of the plurality of stiffeners.